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Abstract:

System for converting mechanical energy such as ocean power into fluid
power which is directed to energy conversion systems or other purposes.
Included are fluid inflatable containers arranged to receive mechanical
energy from a plunger mounted on a shaft, such that the flexible wall of
the container forms a rolling lobe in response to changes in volume,
enclosed within a drum, said shaft running axially through the drum and
coupled to the drum by bearings so that the drum and shaft may move in
relation to one another, a vane runs longitudinally on the drum and
extending radially from an attachment point at the inner surface of the
drum to the surface of the shaft. The mechanical energy is connected
directly or indirectly to either the shaft or to the drum. Mechanical
forces cause the plunger to press into the fluid inflatable container
expelling fluid and creating fluid flow.

Claims:

1. A method for deriving energy from an object in motion by converting
mechanical energy to fluid movement using non-linear motion comprising:
receiving a mechanical input; moving an arced plunger into a first
flexible fluid filled container, wherein the first flexible fluid filled
container is comprised of one of elastomers, coated fabrics, and
multi-ply composites, and wherein fluid is contained within the flexible
fluid filled container; rolling a portion of the first flexible fluid
filled container along an outer surface of the arced plunger; pushing
fluid out of the first flexible fluid filled container; directing the
pushed fluid to a generator; generating electricity using the directed
fluid and the generator; allowing the electricity to travel away from the
generator along an electrical line; and directing the fluid into a second
inflatable fluid container wherein the fluid at least partially fills the
second inflatable container.

2. The method of claim 1 wherein the second inflatable container is
operably connected to an opposing plunger and the opposing plunger is
connected through a vane to the arced plunger, further comprising
suctioning to draw directed fluid into the second inflatable container.

3. The method of claim 1 further comprising: accumulating fluid in an
accumulator.

4. The method of claim 1 further comprising: diverting the pushed fluid
using a diverter.

5. The method of claim 1 wherein the step of directing the pushed fluid
uses a sensor, a computer and a valve to control the flow of the pushed
fluid.

6. The method of claim 1 further comprising: providing a drum to
constrain the first fluid filled container.

7. The method of claim 1 wherein the mechanical input that moves the
arced plunger is created from energy derived from fluid flow.

8. The method of claim 1 wherein the received mechanical input is created
from one of wave, current, tidal, and surf energy.

9. The method of claim 1 further comprising the step of an energy force
creating the mechanical input wherein the energy force is linear.

10. A non-linear system for use in generating electricity from mechanical
energy comprising: a non-linear plunger having a mid-portion with an
arcuate shaped exterior surface wherein the non-linear plunger is
operably connected to a mechanical energy source; a flexible fluid filled
container, operably connected to the non-linear plunger, wherein the
first flexible fluid filled container is comprised of one of elastomers,
coated fabrics, and multi-ply composites, and wherein fluid is contained
within the flexible fluid filled container, wherein a portion of the
flexible fluid filled container is rolled onto the arcuate shaped
exterior surface of the non-linear plunger, such that the non-linear
plunger plunging towards the fluid filled container causes a portion of
the flexible fluid filled container to roll along the arcuate shaped
exterior surface of the plunger; fluid, wherein fluid is expelled from
the flexible fluid filled container when the plunger is moved toward the
flexible fluid filled container by the mechanical energy source; and a
generator to generate electricity using the expelled fluid.

11. The non-linear system of claim 10 wherein the mechanical energy
source is derived from ocean power.

12. The non-linear system of claim 10, further comprising: a device
exerting an opposing force upon the plunger.

13. The non-linear system of claim 10, further comprising a torsion
spring, wherein the torsion spring exerts an opposing force upon the
plunger.

14. The non-linear system of claim 10 further comprising a second plunger
and a second fluid filled container wherein the second plunger is
operably connected through a vane to the first plunger.

15. The non-linear system of claim 10 further comprising a diverter for
diverting fluid.

16. The non-linear system of claim 10 further comprising a computer,
having a processor, a memory and software, that changes velocity of the
expelled fluid.

17. The non-linear system of claim 10 further comprising a drum wherein
the flexible fluid filled container is located inside and constrained by
the drum.

18. The non-linear system of claim 10 wherein the generator comprises a
turbine, an alternator, a controller and an electrical output line.

19. The non-linear system of claim 10 wherein the fluid comprises
hydraulic fluid and the non-linear system further comprises hydraulic
fluid lines and an accumulator.

20. A non-linear system for use in converting an objects movement into
fluid movement comprising: a non-linear plunger having two ends and a
mid-portion with an arcuate shaped exterior surface, the non-linear
plunger operably connected to a moving object; a fluid inflatable
container having a flexible membrane engaging with the non-linear
plunger, wherein the flexible membrane rolls onto the arcuate shaped
exterior surface of the non-linear plunger, such that inflation of the
fluid inflatable container causes a portion of the flexible membrane to
unroll from the arcuate shaped exterior surface of the plunger; an
opposing plunger operably connected to one end of the non-linear plunger;
an opposing fluid container which engages the opposing plunger; and a
fluid communicator, wherein the fluid inflatable container and the
opposing fluid container are in fluid communication, and wherein the
moving object causes the opposing plunger to plunge into the opposing
fluid container causing the opposing fluid container to expel some of its
content.

21. The non-linear system of claim 20 further comprising a volume of
fluid, wherein the volume of fluid is dispersed in the fluid inflatable
container, the opposing fluid container and the fluid communicator,
wherein movement of the object forces fluid to travel through the fluid
communicator.

22. The non-linear system of claim 20 further comprising an accumulator
connected to the fluid communicator.

23. The non-linear system of claim 20 further comprising one of a
uni-directional and bi-directional turbine wherein the turbine is turned
by fluid.

24. The non-linear system of claim 20 further comprising an alternator.

25. The non-linear system of claim 20 further comprising a diverter valve
connected to the fluid communicator.

26. The non-linear system of claim 20 further comprising a computer with
software to monitor the fluid flow.

27. The non-linear system of claim 1 further comprising a drum which
houses the non-linear plunger, opposing plunger, fluid inflatable
container and opposing fluid inflatable container; wherein the drum is
attached to one of a seabed or a first buoy.

28. The non-linear system of claim 27 further comprising a vane which is
operably connected to one of a wall or a second buoy.

29. The non-linear system of claim 27 wherein the drum is in a horizontal
orientation and the system further comprising a vertical drum operably
connected to the horizontally oriented drum.

30. An apparatus comprising: a drum; a shaft passing longitudinally
through the drum; two or more casters, operably connected to the drum and
the shaft, wherein the shaft and the drum move relative to each other; a
non-linear plunger housed within the drum and connected to the shaft; a
first fluid inflatable container housed within the drum and operably
connected to the plunger, wherein the first fluid inflatable container
comprises a flexible membrane which rolls when deflated; a second fluid
inflatable container housed within the drum and in fluid communication
with the first fluid container; wherein relative motion between a shaft
and the drum will cause non-linear movement of the non-linear plunger
within the drum and, when the non-linear movement of the non-linear
plunger is towards the first fluid inflatable container, the non-linear
movement will cause fluid to move from the first fluid container to the
second fluid container.

31. The apparatus of claim 30 wherein the second fluid inflatable
container comprises a flexible membrane, the apparatus further comprising
a second plunger connected to the non-linear plunger and operably
connected to the second fluid inflatable container.

[0002] The technical field relates to systems and methods for the
conversion of mechanical energy into fluid power.

BACKGROUND

[0003] Current systems and methods for converting mechanical energy into
fluid power generally rely on pistons moving within cylinders,
centrifugal rotors and/or gear rotors. These systems require large
precision machined surfaces, complex hydraulics, numerous parts and
components, and very tight tolerances to prevent hydraulic or fluid
leakage. These systems are suited for compact power units and/or high
volume fluid flow at high pressures, there is a need for a low-cost,
robust technology for converting regular periodic mechanical motion, such
as that produced by ocean waves or slow moving machinery, into a flow of
fluid power.

SUMMARY

[0004] An embodiment of a system for converting mechanical energy into
fluid power includes a fluid and one or more fluid inflatable containers
which are arranged to receive mechanical energy from a plunger mounted on
a shaft, such that the flexible wall of the fluid inflatable container
forms a rolling lobe in response to changes in volume, enclosed within a
cylindrical enclosure or drum, said shaft running axially through the
center of the drum and coupled to the drum by bearings so that the drum
and shaft may move freely in relation to one another, one or more vanes
running longitudinally down the length of the drum and extending radially
from their attachment point at the inner surface of the drum to the
surface of the shaft. The source of mechanical energy may be connected
directly or indirectly to either the shaft or to the drum. The fluid
inflatable containers are arranged in a whole or partial annular ring
inside of the drum around the shaft so that each container exerts
expansive force between a vane fixed to the drum and the one or more
plungers fixed to the shaft. A volume of the fluid is placed in the one
or more fluid inflatable containers. Mechanical force or motion applied
to the system causes the plunger to press into the fluid inflatable
container, forming a rolling lobe that eliminates most of the friction
between the fluid inflatable container and the inner surface of the drum,
and expels fluid creating fluid flow, which can be directed to an energy
conversion system or other purpose. The system may include valves to
produce a uni-directional flow of fluid produced in response to
mechanical motion in the system, and accumulators, pressure vessels,
and/or other fluid power storage devices may be used to smooth out the
flow of power output from the system. In an embodiment an arced or curved
plunger is used to assist in creating the rolling lobe. The plunger and
rolling lobe system may be configured to operate in non-linear or
semi-circular rotation upon application of mechanical force to either the
shaft or the drum.

[0005] The system may incorporate use of one or more elastic tensioning
devices to bias the system in a specific position, to return the system
to starting position after each stroke or cycle, or to tune the resonant
frequency of the system to better suit the operating conditions. In one
embodiment, a computer with a processor and memory is used to monitor and
control the system. The system may be deployed at sea to generate
electricity.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 shows a cutaway view of an embodiment of a system for
converting mechanical energy to fluid power in the top dead center
position with main component parts in position.

[0007] FIG. 2 shows a view of an embodiment of a system for converting
mechanical energy to fluid power with an arced actuator rotated to
approximately 90° counter-clockwise position without the rolling
lobe sections shown.

[0008] FIG. 3A shows a cutaway view of an embodiment of a system for
converting mechanical energy to fluid power with a movable member
transferring external force to the shaft to move an arced actuator in a
repeatable arced motion.

[0009] FIG. 3B shows a partial cutaway view of an embodiment of a system
for converting mechanical energy to fluid power showing the rotation of
the plunger inside the boot and without the rolling lobe sections shown,
as well as exemplary additional components for converting the flow of
fluid power to electricity.

[0010] FIG. 4 shows a close-up partial cutaway view of an embodiment of a
system for converting mechanical energy to fluid power using limited
arcuate motion and fluid inflatable containers.

[0011] FIG. 5 shows three versions of the many possible configurations of
plungers that force the fluid inflatable container to form a rolling lobe
as they travel through an arcuate path inside the drum

[0012] FIG. 6 shows an example of one of the lower sections of a fluid
inflatable container.

[0013] FIG. 7 shows an example of the upper section of a fluid inflatable
container to form a rolling lobe.

[0014] FIG. 8 shows a close-up partial cutaway view of an embodiment of a
system for converting mechanical energy to fluid power, showing one
plunger pressing into a fluid inflatable container.

[0015] FIGS. 9A, 9B, and 9C show the use of one or more elastic tensioning
devices to bias the system in a specific position, to return the system
to starting position after each stroke or cycle, or to tune the resonant
frequency of the system to better suit the operating conditions.

[0016] FIGS. 10A and 10B show a system of bearings that hold the shaft in
an embodiment of a system for converting mechanical energy to fluid
power.

[0017] FIG. 11A shows a prior art system for converting the energy of
reciprocating ocean wave energy into fluid power.

[0018] FIG. 11B shows an embodiment of the system deployed in a wave or
tidal current energy producing device such as a reciprocating linear
motion attenuator.

[0019] FIG. 12 shows the system deployed in a wave or tidal energy
producing device such as a wave flap.

[0020] FIG. 13A, the prior art portion of a sea surface system of tethered
buoys used for converting the motion of surface ocean waves into fluid
power is shown.

[0021] FIG. 13B, shows an embodiment of the system mounted at the junction
of a chain of linked, tethered buoys, which float in the waves on the
surface of the ocean.

[0022] FIG. 13C shows a more detailed depiction of the location of the
system at the linkages of a series of tethered buoys positioned to
capture mechanical energy from the buoys' reciprocating vertical and
horizontal motion relative to one another

[0023] FIG. 14 shows the fluid circuit from the rolling lobe and plunger
system to a hydraulic motor and generator to produce electricity under
computer control.

[0024] FIG. 15 shows a manifold and check valve schematic that enables
reciprocating mechanical force to direct fluid through the turbine
generator in one direction rather than require a bi-directional turbine
generator.

[0025] FIG. 16 shows the use of an accumulator device in the circuit to
smooth the fluid flow.

DETAILED DESCRIPTION

[0026] An enduring challenge is posed by the high cost and fragility of
machines used to convert mechanical motion produced by natural systems,
such as ocean waves, into useful power. Many such devices rely on
conversion of the reciprocating motion of waves into mechanical rotary
power or into fluid power by use of pistons such as wave attenuator
devices described in U.S. Pat. No. 4,672,222 or wave flap systems as
described in PCT Publication Number WO/2006/100436 published Sep. 28,
2006 for International Application Number GB2006/000906. Such systems are
not well suited to the harsh environments where they are deployed such as
the ocean or tidewaters, where machined parts, piston shafts, piston
seals, gears, motors and pumps may be damaged by water, salt, sand,
organic material and other hazards. Additionally if such systems are
complicated and prone to breakdown they will be much less manageable when
situated in the ocean surface or in breaking waves. There is thus a need
for a robust, simple alternative to traditional hydraulic pistons or
gears for converting reciprocating motion collected from mechanical
sources such as machinery and ocean waves into usable fluid power.

[0027] Existing examples of wave and ocean power generating systems using
traditional pistons or gear systems include the Oyster wave flap system
from Aquamarine Power Ltd., Elder House, 24 Elder Street Edinburgh EH1
3DX, Scotland, UK, described in PCT Application Number GB2006/000906, the
WaveRoller from AW Energy Ltd. AW-Energy Oy, Kolamiilunkuja 6, FI-01730
Vantaa Finland, described in the PCT Publication Number WO/2007/125156
and the Pelamis "Sea Snake" type surface wave attenuator system from
Pelamis Wave Power, Ltd., 31 Bath Rd, Leith, Edinburgh, EH6 7AH,
Scotland, UK and described in PCT Publication Number WO/2004/088129,
published on Oct. 14, 2004 for International Patent Application Number
PCT/GB2004/001443.

[0028] The applicant previously described a non-linear actuator system
which can be used to produce a large amount of precisely controlled
mechanical force without the expense of numerous precision machined
components and surfaces, in International Patent Application
PCT/US2010/000220 entitled "Non-Linear Actuator System and Method" filed
Jan. 27, 2010 which is incorporated by reference as if fully set forth
herein. The non-linear system and variations of the non-linear system
described can be also used to produce fluid power from reciprocating
arcuate mechanical motion. For example, the same or similar arrangement
of fluid inflatable containers can be used in reverse to produce a pump
that converts mechanical work into fluid power. By applying a mechanical
force to either the shaft or the drum, fluid inflatable containers are
compressed and fluid power is produced. The fluid power can be used for
many useful purposes, for example to power a common hydraulic motor
turning a generator and thus producing electrical current. The addition
of a valve manifold as described herein and common in prior art makes the
fluid flow uni-directional for ease of application in various fluid power
systems. The resulting fluid power can be stored in accumulators, and
used for many purposes including, but not limited to, the driving of
hydraulic motors for the generation of electricity and the pressurization
of reverse osmosis desalination systems.

[0029] Referring to FIG. 1, an embodiment of a system 100 for converting
mechanical energy to fluid power includes a shaft 116 to which is fixed a
vane 120, which is operatively coupled to and runs longitudinally through
the center of a drum 104. Bearings (not shown) hold the shaft 116 in a
central axial position within the drum 104. Reciprocating mechanical
power may be applied or transferred to either the drum 104 or the shaft
116. The plungers 124',124'' or pistons 124',124'' are mounted to each
side of the vane 120, and may be fixed with bolts or other fasteners.

[0030] A fluid inflatable container 140',140'' consisting of a rigid
section or "boot" 136',136'' and a flexible section or "sleeve"
112',112'' is arranged so that it is in contact with the end of the
plunger 124',124'' opposite the vane 120. Fluid is introduced through the
fill ports (not shown), which may be located in the boot 136.

[0031] The sleeve 112 portion inflates and moves into the clearance
between the surface of the vane 120 and the drum 104 by rolling along the
surface of the vane 120. Reciprocating mechanical motion causes the shaft
116 to rotate in the drum 104 and the shaft exerts a force on the plunger
124',124'' and forces the plunger 124',124'' against the sleeve 112
causing hydraulic pressure to build in the fluid inflatable container and
forcing fluid through the fluid power manifold (not shown) from which
fluid is returned to the opposite fluid inflatable container. As one
fluid inflatable container 140',140'' is compressed and deflated, the
plunger 124',124'' moves towards or into the opposite container and is
forced into the boot 136',136'', forcing the sleeve 112 to invert upon
itself and form a rolling lobe as the sleeve 112 is rolled off the drum
104 wall. As the mechanical force reciprocates, the fluid is forced back
through the system. In this embodiment, the boots 136',136'' are bolted
to the drum 104.

[0032] In an alternate embodiment, the boots 136',136'' may be bolted to
each other or fitted into the drum 104 without being bolted to each other
or the drum 104. Alternatively, the vane 148 may be formed by two
surfaces of the boots 136',136'' in contact with each other when the
boots 136',136'' are made of a rigid or semi-rigid material. In this
embodiment, the system 100 is shown positioned at the top dead center
position 144. The rolling lobe sleeve 112 is not required to slide along
the wall of the drum 104, and this allows the system 100 to operate with
little or almost no internal friction. The fluid inflatable containers
140 may be entirely formed from the same material as the flexible sleeve
portion. The containers 140 may also have other features formed into them
such as mechanical attachment features to connect the containers to the
plungers and/or the fixed vane 148.

[0033] The arcuate motion of the system 100 can be extreme because the
fluid inflatable container 140',140'' does not need to resist the large
stresses that would build up in an unconstrained fluid inflated
container. The plunger 124',124'' is guided in an arcuate path by the
rotation of the shaft 116, so that little or no internal friction will be
generated within the fluid inflatable container 140',140''.

[0034] Referring now to FIG. 2, shown is an embodiment of system 100 for
producing fluid power from reciprocating mechanical motion. The source of
mechanical power (not shown) may be rotated through at least a
180° range of motion as the rolling lobe sleeves 112 (not shown)
move from almost fully extended on one side, to almost fully retracted on
the other side. Various embodiments of system 100 can be rotated through
at least a 180° range of motion. The rigid portion or boot
136',136'' can be made smaller to accommodate ranges of motion of greater
than 180°, such as 270° or more. In an embodiment, the
rigid portion or boot is not required, and the entire fluid inflatable
container is made into a bladder of the same material with the same
properties throughout. Low friction coatings or materials, or lubricants
may be used to reduce the friction of the shaft 116 against the boot
sections 136 of the fluid inflatable containers 140.

[0035] Referring now to FIG. 3A, shown is a cutaway view of an embodiment
of a system 100 for converting mechanical energy to fluid power. An
external force 900 applied upon a movable member 840 is transferred to
either the shaft 116 or the drum 104 (depending on which is connected to
the movable member 840) and is thereby made to move the arced actuator
200 in a repeatable arced motion. In the embodiment shown in FIG. 3A, a
movable member 840 is operably connected to the shaft 116. A system of
plungers 200 are shown in this embodiment. The plunger 200 is shown
attached to the shaft 116 along a longitudinal axis. Referring now to
FIG. 3B, shown is an embodiment of a system 100 for converting
reciprocating mechanical motion into electricity. The action of external
force 900 applied to the movable member 840 is transferred to the shaft
116 causing rotation of the plungers 200 thereby compressing the fluid
inflatable containers (not shown) thus forcing fluid through a hydraulic
manifold system 250 which directs the fluid power for example to a
turbine generator 270 so as to produce electric current. The turbine can
be bi-directional to convert the reciprocating fluid flow into rotary
energy, or uni-directional when a series of check valves 255 are used to
direct fluid power to the turbine in a single direction, as the
mechanical force 900 reciprocates back and forth. An accumulator 260 may
also be incorporated to allow storage of fluid power and to smooth the
flow of fluid through the turbine 270.

[0036] Referring now to FIG. 4 a fluid inflatable container 140',140'' is
shown within the housing 104 wherein the first plunger 124' is engaged by
the first fluid inflatable container 140'. The second fluid inflatable
container 140',140'' is shown constrained by the housing wherein the
second plunger 124'' is engaged by the second fluid inflatable container
140''. In this embodiment the two plungers 124',124'' are shaped to allow
a plunger 124',124'' to slide fully into the boot 136',136'' section of a
fluid inflatable containers 140',140'' without striking the walls and
without damaging the fluid inflatable containers' 140',140'' and without
compressing the boot 136',136'' sections.

[0037] Referring now to FIG. 5, shown are examples of various possible
shapes of a plunger 124. These plungers 124a-124c are shown curving to
the left. Plungers 124a-124c may similarly curve to the right. The
plungers 124a-124c are shaped to provide a space between the wall of the
drum 104 (not shown) and the side wall of the plungers 124a-124c
sufficient to allow a rolling lobe (not shown) to form in the membrane of
the fluid inflatable containers (not shown). The plunger 124a is shown
with a curved, hollow shell that may be filled with a high density
material such as concrete, foamed concrete, or another semi-plastic
material. The material used to fill the plunger 124a may be selected
based on its effect on the buoyancy of the overall system. Plunger 124b
is an alternative solid, plunger shape where one of the surfaces is
straight 150 and one of the sides is curved 152. Plunger 124c is shown as
a solid plunger with two arced sides 154,156. The bottom surfaces of the
plungers 124a-124c come in contact with the fluid inflatable containers
140',140''. The length of a plunger 124 helps determine the plungers
124',124'' range of motion.

[0038] In an embodiment, the rolling lobe sleeve 112 may be coupled to a
bottom surface of a plunger 124',124''. A plungers 124',124'' may be
constructed of steel, aluminum, plastic, or any other sufficiently strong
rigid or semi-rigid material. It may include reinforcing ribs within to
counter the forces imposed by the mechanical energy or the pressure
transmitted by the fluid inflatable container 140',140''. The plunger
124',124'' is slightly tapered to allow the plunger 124',124'' to
smoothly displace and move the walls of the fluid inflatable container
140',140''. The plunger 124',124'' may include a smooth outside wall and
radiused corners to avoid damage to the fluid inflatable container
140',140''. In one embodiment, the plunger 124',124'' is be sized so that
the gap between the drum 104 wall and the plunger 124',124'' does not
exceed the maximum unsupported radius of the material making up the fluid
inflatable container 140',140'' at the system's working pressure.

[0039] Referring now to FIG. 6, in one embodiment the fluid inflatable
containers 140',140'' are made up of a lower section or boot 136 which
may be a rigidly molded plastic, elastomer, or metal. This section may be
continuously molded with the sleeve 112 or flexible section that forms
the rolling lobe. Alternatively, it may be formed like a tire with a bead
that may be swaged or otherwise coupled to the sleeve 112. The boot 136
section need only be rigid enough in operation to resist deformation and
ensure that the rolling lobe sleeve 112 is the only portion of the fluid
inflatable container 140',140'' that substantially deforms in response to
changes in fluid pressure and volume. In many applications, the fluid
containers' 140', 140'' internal pressure will be sufficient to eliminate
the need for a distinct boot section 136. The boot 136 may incorporate a
metal plate to connect it to the vane 120 in the drum 104. The boot 136
is operatively coupled to the rolling lobe sleeve 112. The boot 136
typically fills a quadrant of the drum 104, for example the lower left or
right quadrant.

[0040] Referring now to FIG. 7, in one embodiment the fluid inflatable
containers 140',140'' are also comprised of a rolling lobe sleeve 112
which may be smaller than the volume that it will expand to fill as it is
pressurized. The lobe sleeve 112 is coupled to the boot 136',136'' on one
end and the plunger 124',124'' at the other. In one embodiment, the lobe
sleeve 112 is connected to the bottom of the plunger 124', 124''. Once
all the components are coupled, the fluid inflatable container 140',140''
is complete. This embodiment thus provides fluid communication between
the boot 136',136'', the sleeve 112 and the plunger 124',124''.

[0041] Referring now to FIG. 8, in one embodiment the fluid inflatable
containers 140 are simple cells that consist only of a flexible membrane
such as a heat sealed, urethane coated nylon fabric with a single fill
port. The fluid inflatable container 140 can also be made out of
elastomers, coated fabrics, multi-ply composites, or any material that
can contain the fluid flexibly. In one embodiment, the fluid inflatable
container 140 is shaped to fill slightly more than one half of the drum
104 at full inflation. The fluid inflatable containers 140 may have
features that allow for mechanical attachment of the top face of the
fluid inflatable container 140 to the bottom of the plunger 124 such as
Velcro pads, grommets, or metal loops for straps. Mechanical attachments
provide greater certainty that the fluid inflatable container 140 will
remain in the proper position in the enclosure. The motion of the plunger
124 combined with the internal pressure of the fluid inflatable container
140 forces the wall of the fluid inflatable container 140 to form a
rolling lobe against the wall of the drum 104 as the plunger 124 travels
its arcuate path.

[0042] The system 100 can operate in a very wide range of pressures. For
example, in some applications the system may operate at a relatively low
pressure of 150 psi, in other applications as at much higher pressures in
the range of 1500 psi -1700 psi. Typically, the determining factor as to
the operating pressure is the ability of the fluid inflatable containers
140 to withstand the internal pressure generated by mechanical
compression of the containers by the plunger 124 over the unsupported
radius of the fluid inflatable container at the rolling lobe. For
example, where the plunger is a maximum of 3 inches away from the inner
wall of the drum 104, and the walls of the fluid inflatable container are
0.25 inches thick, the maximum unsupported radius is about 2.5 inches.
Under these conditions, the fluid inflatable containers 140 would need a
wall tensile rating in pounds per square inch at least 2.5 times greater
than the pressure in pounds per square inch generated by the mechanical
compression of the plungers 124. One skilled in the art will appreciate
that a safety factor over and above the tensile limit will generally be
specified, and that particular reinforcement may be required around the
port leading into the fluid inflatable containers 140.

[0043] In some embodiments, the fluid pressure is used to return the
system 100 to an equilibrium state or neutral location for the vane 120
and shaft 116. In some embodiments, the neutral position places the vane
120 in the middle or center of the system 100. In another embodiment,
regulation of fluid pressure and flow within the system can also help to
regulate the speed of mechanical equipment. In yet other embodiments,
high fluid pressure allows the system 100 to resist movement when the
system 100 is not in use.

[0044] The plunger 124',124'' may constructed by any of a number of
typical industrial processes such as injection molding, drawing, assembly
of cut parts into a weldment, or by casting and machining. The plunger
124',124'' may have smooth sides, and a tapered shape in the wall from
the vane 120 to the bottom. In some applications it may be useful to
create very heavy plungers 124',124'' that can serve as counterweights to
the mechanical energy source, plungers 124',124'' may also be filled with
high-density materials such as liquids, concrete, composites or ceramics
to add to the counterweight effect. The materials used to fill the
plungers 124', 124'' can also be used to control the buoyancy of the
entire system (not shown). Plungers 124',124'' filled with concrete are
cost efficient to produce as the shell of the plungers 124',124'' may be
made of cheaper, light-weight materials which travel easier. The
lightweight shells are then filled with concrete or other high-density
materials. The filling process can occur on-site to reduce transportation
costs. In an embodiment, plungers 124',124'' have internal structures
such as framing or ribs for stability or strength.

[0045] Tolerances on the plunger 124',124'' can be large, on the order of
1/4'' or more, as the plunger 124',124'' is a non-precision component.
The plunger 124',124'' may have a smooth outer surface to avoid damage to
the fluid inflatable containers 140',140'' and be tapered to allow smooth
motion. The vane 120 and the plungers 124',124'' are subjected to large
forces as they transmit mechanical force to the fluid inflatable
containers 140',140'', and so it is preferred if the plunger 124',124''
is capable of withstanding large amounts of force on the sides and bottom
without significant or permanent deformation. The forces on the plunger
124',124'' will be directly related to the pressure created in the fluid
inflatable container 140',140'' and the surface area of the fluid
inflatable container 140',140'' in contact with the plunger 124',124''. A
single-plunger vane assembly may be created by substituting two plungers
124',124'' with a single, "two-headed" plunger. The two-headed plunger
may be a single assembly and may include the vane 120 and be connected
directly to the shaft 116.

[0046] The arcuate motion received by an embodiment of this invention is
not limited to a circular path as shown in the drawings. So long as the
motion of the plunger 124',124'' is guided through an arcuate path
similar to the curvature of the enclosure surrounding the fluid
inflatable containers 140',140'', the mechanical energy can be converted
into fluid power. The movement and curvature of the enclosure can be
similar in shape. The acceptable mechanical energy input arc is based
upon the movement of the shaft 116, movable member, or non-stator portion
of the actuator. The mechanical input or energy may be arcuate or linear
and it may be reciprocating or non-reciprocating.

[0047] Various non-linear mechanical input is acceptable including
crescent shaped, oval shaped, rotary, curves and other irregular
patterns. The fluid inflatable container 140',140'' may be charged with
varying amounts of non-volatile gas or fluid. In an embodiment, the fluid
may be air, water (including but not limited to groundwater, river water,
seawater, brackish water, glycol-water mixes), gas, oil, high-density
fluid, high-pressure hydraulic fluid, electro reactive fluid, and high
viscosity fluid. In an embodiment, the fluid may contain suspended
magnetic particles such that when the fluid passes a coil of wire, a
current flow is induced in the coil. In another embodiment, the fluid may
be conductive such that when the fluid passes an electromagnet, a current
flow is induced in the fluid.

[0048] Referring now to FIGS. 9A, 9B and 9C, shown are side and frontal
views of various exemplary spring arrangements that may be used to
stabilize the shaft 116, to bias the system in a given orientation. In
FIG. 9A, an embodiment is shown which employs two torsion springs 700'
and 700'' to stabilize the shaft 116 with relation to the drum 104. The
spring or springs 700' and/or 700'' can also be used to tune the resonant
response of the entire system for collecting energy (not shown). By
adjusting the spring constant and pre-load of the springs 700' and/or
700'' and the pressure at which the system operates, the natural resonant
frequency of the entire system can be tuned. In FIG. 9B, torsion springs
710' and/or 710'' are shown stabilizing the shaft 116 in relation to the
drum 104'. In FIG. 9C, the system is shown with power springs 730' and/or
730'' positioned in relation to the drum 704.

[0049] Referring now to FIG. 10A and 10B, shown are side and frontal views
of an exemplary rotating assembly 804 for use in an embodiment of the
system for converting mechanical energy to fluid power, respectively. The
rotating assembly 804 is an example of a component that can be used for
bearings in system 100.

[0050] Referring to FIG. 10B, shown are three or more casters 440 mounted
on the drum 104 (not particularly depicted) and arranged such that the
shaft 116 is supported and can freely rotate in the center of the drum
104. Each of the casters 440 is attached to the rotating assembly 804
with one or more bolts 442. Each of the casters 440 is directly or
indirectly attached to the drum 104. The rotating assembly 804 may be
mounted outside of the drum 104, on an outside surface such as an end cap
of a drum 104. The rotating assembly 804 may also be mounted inside the
drum 104 on the inside of an end cap of the drum 104, for example. The
rotating assembly 804 may also be connected to the drum 104 by a frame
holding the rotating assembly 804 in place.

[0051] The casters 440 may be easily removed for field service. A caster
440 can be more easily replaced when it is not in contact with the shaft
116. In one embodiment, one or more casters 440 is adjustable so that it
may be moved away from the shaft to create a small tolerance within which
the shaft 116 may be moved radially away from each of the casters 440. In
this manner, casters 440 may be replaced one at a time. In another
embodiment all of the casters 440 are adjustable and the rotating
assembly is integrated into the endplate of the system 100, the shaft 116
is moved by employing a conventional hydraulic or mechanical jack. The
jack can be removed once a caster 440 is replaced and the one or more
adjustable casters are tensioned to firmly hold the shaft 116 in
position. The shaft 116 typically runs radially through the central axis
of the drum 104. The casters 440 can be replaced without disassembling
the rotating assembly 804 or removing the shaft 116 and without removing
other casters 440. Given the very harsh conditions that a system 100 is
expected to operate in, the rotating assembly 804 provides a low-cost
method of providing a bearing, while also offering easy serviceability.

[0052] Referring now to FIG. 11A, shown is an embodiment of a prior art
system for converting the energy of reciprocating ocean wave energy into
fluid power. The prior art system 600 consists of a wave attenuating wall
840 which is connected to a frame 826 on the seafloor, by a hinge 827. As
the wall 840 reciprocates, a hydraulic piston 825 connected to the wall
840 is forced back and forth within a hydraulic cylinder 820 mounted on
the frame 826. The reciprocating mechanical motion of the ocean waves is
thus converted into fluid power which can be used for power generation or
other useful purposes. A drawback of this prior art is the reliance on
conventional hydraulic cylinders which are ill suited to long-term use in
the hostile undersea environment.

[0053] Referring now to FIG. 11B, an exemplary system 700 utilizing an
embodiment of the apparatus for converting mechanical energy into fluid
power 100 is shown applied for the conversion of ocean wave or current
power into fluid power. In this embodiment the system 100 converts the
reciprocating motion of ocean waves (not shown) into fluid power by the
use of a flap 840 hinged to a frame 826 anchored to the sea floor (not
shown) and extending through the surface of the water. In one embodiment,
the shaft 116 is fixed to the frame 826 while the drum 104 is fixed to
the flap 840. In another embodiment, the drum 104 is fixed to the frame
826, while the shaft 116 is fixed to the flap. In either embodiment,
relative mechanical motion is created in the converting system 100 to
move fluid. In one embodiment, the shaft 116 of the system 100, is turned
by the action of the waves against the flap 840, which alternately
compresses the fluid inflatable containers (not shown) to create a
bidrectional flow of fluid power or, when coupled to a valve manifold
with an appropriate arrangement of one-way valves (not shown), a
unidirectional flow of fluid power. The fluid power may be used to power
a hydraulic motor or turbine (not shown) coupled to a generator (not
shown), and may thus generate electricity. The pressurized fluid may also
be used to compress seawater for reverse osmosis desalination.

[0054] FIG. 11B shows two drum-shaped converting systems 100 one on each
end of the wall. Any number of drum shaped converting systems 100 may be
used, for example one in the center of the wall or three with one in the
center and two on the ends or outer portion of the wall. In larger
embodiments, four or more converting systems 100 may be used. Each of
these systems 100 may be connected to a hydraulic motor or turbine (not
shown) or multiple systems 100 may be connected to one hydraulic motor or
turbine.

[0055] Referring now to FIG. 12, an apparatus for absorbing and converting
tidal energy 1200 is shown fixed to the seafloor. An embodiment of the
converting system 100 is shown with the shaft coupled to a wave flap 840
anchored to the seafloor. The flap 840 absorbs tidal energy 1000 in two
directions, incoming and outgoing, and causes the plungers (not shown) to
alternately compress one of the two fluid inflatable containers (not
shown). The alternate compression of the fluid inflatable containers
creates a bidirectional flow of fluid power or, when coupled to a valve
manifold with an appropriate arrangement of one-way valves (not shown), a
uni-directional flow of fluid power. The resulting fluid power may be
used to power a hydraulic motor or turbine (not shown) coupled to a
generator (not shown), or for other useful purposes as described herein.
Many variations of the apparatus for absorbing and converting tidal
energy 1200 using the converting system 100 are available. For example,
more or less wave flaps 840 may be used, various means of fixing the
apparatus 1200 to the sea floor are possible, any number of converting
systems 100 may be connected and used, and the converting systems 100 may
be operably connected to one or more turbines (not shown).

[0056] Referring now to FIG. 13A, the prior art of a sea surface system
1100 of tethered buoys 1120 used for converting the motion of surface
ocean waves into fluid power is shown. The motion of the surface waves
causes each of the tethered buoys 1120 to move relative to one another
and this mechanical motion is used to generate fluid power. For a more
specific description of this prior art sea surface system 1100 see
WO/2004/088129. A drawback of this prior art sea surface system 1100 is
the reliance on conventional hydraulic cylinders mounted at the junctions
of the tethered buoys (not specifically shown) to convert the mechanical
motion of the tethered buoys 1120 into fluid power. Conventional
hydraulic cylinders are not well suited to prolonged service submerged in
a marine environment.

[0057] Referring now to FIG. 13B, an embodiment of the converting system
100 is mounted at the junctions of a chain of linked, tethered buoys
1120, which float in the waves on the surface of the ocean. The buoys
move relative to one another as they absorb ocean wave energy, which in
turn causes the shaft 116 of the system 100 to rotate compressing the
plungers 124 alternately into the fluid inflatable containers (not
shown). The resulting fluid power can then be used for electric power
generation as explained herein or for other useful purposes as described
herein. The converting systems 100 may be arranged in horizontal or
vertical planes between or connected to two of the tethered buoys.

[0058] Referring now to FIG. 13C a more detailed depiction of location of
the invention at the linkages of a series of tethered buoys
1120',1120'',1120''' is shown. The invention is positioned to capture
mechanical energy from the ocean waves which force the buoys 1120',
1120'',1120''' to reciprocate up and down and horizontally relative to
one another. In the embodiment shown, each tethered buoy is connected to
the next with two separate systems 100. One system 100 is placed in a
horizontal orientation and one in a vertical orientation. A shaft 116
connects the two systems. In an embodiment a frame or bracket connects
the shaft 116 of one system 100 to a system 100 on an adjacent buoy so
that upon relative motion of the two adjacent buoys mechanical energy
from waves is transferred and causes the shaft 116 of each system 100 to
rotate. In this configuration, mechanical motion from at least two
directions is captured and the energy converted into fluid motion. In
another embodiment, in which only one converting system 100 is used
between buoys, a horizontally placed system 100 is located between buoys
1120' and 1120'', and a vertically placed system 100 is located between
buoys 1120'' and 1120', In one embodiment, the shaft 116 is connected to
one buoy, while the drum 104 is connected to the adjoining buoy. The
buoys move relative to one another as they absorb ocean wave energy,
which in turn causes the shaft 116 to rotate compressing the plungers 124
alternately into the fluid inflatable containers (not shown). The
resulting fluid power can then be used for electric power generation as
explained herein or for other useful purposes as described herein.

[0059] As shown in more detail in FIG. 14, regardless of the source of the
mechanical motion, the reciprocating motion and mechanical force (not
shown) upon the moveable member (not shown) is translated to rotary
motion by the system 100 either by rotating the drum 104, or the shaft
116. This relative motion of or between the drum 104 and shaft 116 causes
the plungers 124', 124'' to compress the fluid inflatable containers
112', 112'' generating alternating flows of fluid from one fluid
inflatable container 112', 112'' to the other 112, 112'' through hoses
300 to the manifold 250. As the fluid (not shown) flows through the
manifold 250 individual check valves (not shown) convert the
reciprocating fluid flow into uni-directional flow through the hydraulic
motor or turbine 270 which drives an alternator 280 to produce electric
current (not shown) which is transmitted wherever desired. In one
embodiment, fluid is stored in a reservoir (not shown) and flows between
the reservoir and the containers 112', 112'' and does not flow between
the two inflatable containers 112', 112''.

[0060] The system to generate electricity of FIG. 14 is monitored by a
computing system 230 which receives data from multiple sensors 232 and
which may control the flow of fluid through the system using
electronically actuated variable valves (not shown) and thus controlling
the speed of the hydraulic motor or turbine 270. In one embodiment, the
computing system 230 is used to increase or decrease the pressure of the
fluid in the inflatable containers 112', 112''. With sensors such as 232,
the computing system 230 can in real-time and substantially
instantaneously change the pressure in the inflatable containers. This
can be done by the computing system 230 controlling the valves (not
shown), the turbine or an accumulator. If the computing system 230
software (not shown) learns from a sensor 232 that the velocity of the
fluid flow is higher than desired or lower than desired, it can quickly
change the pressure (up or down) and increase or decrease the velocity of
the fluid flow. In one embodiment, computing system 230 and its software
improves the performance and efficiency of the overall systems to
generate electricity. In an embodiment multiple systems 100 can be
arranged to collect energy from different points on the seabed and
transmit pressurized fluid to a single turbine 270 and alternator 280 for
power generation. This reduces the need for multiple turbines 270 and
alternators 280 as well as other related components.

[0061] Referring now to FIG. 15, a schematic of an exemplary valve
manifold 250 is shown for converting the alternating fluid flow from the
system for converting mechanical energy to fluid power 100 into
uni-directional flow. A series of check valves 255 are arranged as shown
so that flow from a fluid inflatable container (not shown) passes from a
port in the system for converting mechanical energy to fluid power 100,
into and out of the manifold through hoses 300. By action of the check
valves 255, the fluid is channeled in a single direction through the
hydraulic motor 400 or turbine 270 and returns to the opposite fluid
inflatable container (not shown) through the manifold 250, and hose 300.
In an embodiment, several systems 100 may feed into a single manifold and
power a single hydraulic motor 270, thereby reducing the complexity of
the overall power collection system. The use of such an arrangement of
check valves and other components is discussed in the prior art. For a
detailed description of such hydraulic circuits see FIGS. 11a, 11b & 12,
in PCT/GB2004/0001443 and the accompanying discussion in the
specification therein which is hereby incorporated by reference.

[0062] Referring to the next FIG. 16 an alternative embodiment is shown
which incorporates an accumulator 260 and charging circuit 600, including
a flow limiting valve 620 to limit and smooth out the flow through the
turbine 270 or hydraulic motor 400 to produce a more constant speed
output and thereby improve the quality of the electricity (not shown)
produced by the alternator (not shown). Additional hydraulic and
electrical circuits of conventional types may be used to further
condition the electrical output of the system. For example, the use of a
flywheel to smooth the output of the electric power generator is
discussed in PCT Publication No. WO2006/100436, published Sep. 28, 2006.
Additional software and controllers may be used to control, monitor,
smooth and improve system performance.